Hi Nicolas,
The error you get is due to the fact that the LearningFrequency property in the rlPPOAgentOptions class was introduced in MATLAB R2024a release. You can check the version history of the class(or any other function) in the Version History section of the documentation page: https://www.mathworks.com/help/reinforcement-learning/ref/rl.option.rlppoagentoptions.html#mw_abe4fee0-4021-4936-a3a1-5bc7c8e85cbc
Also, you can refer the release notes for R2024a for all the new updates to the Reinforcement Learning Toolbox here: https://www.mathworks.com/help/reinforcement-learning/release-notes.html
